What They Can And Can’t Do For Air Cargo

Turning a passenger aircraft into a full-fledged freighter is more involving than simply removing seats. The floor has to be strengthened, a hole needs to be cut in the fuselage for a loading hatch, and weeks of additional work is required. So instead Air Canada in six days designed and implemented a solution to make three 777-300ER aircraft into hybrid or quasi freighters.

Air Canada is taking out all of the plane’s 422 economy and premium economy seats, more than doubling the floor space for cargo.

Two 777s have been converted and are flying to Tokyo and Shanghai. The final third aircraft is expected to be completed soon. Air Canada has operated 40 all-cargo flights since March 22 and plans to operate up to 20 weekly cargo-only flights with the quasi-777 freighters as well as regular 777s and 787s.

Conservative weight restrictions: Air Canada is retaining the existing aircraft cabin floor, which is designed to support seats, people and carry-on luggage – not densely stacked cargo. A full freighter conversion sees the floor strengthened to withstand heavy cargo.

Air Canada is being conservative with payload. It is allowing a maximum of 2,907 pounds in the center of one cabin section (full aircraft details are not disclosed). That area normally has 48 passenger seats, which would weigh 8,160 pounds if all of those seats were occupied by 170-pound passengers (excluding the weight of the seats and carry-on luggage).

Light weight cargo only: The weight restriction is not necessarily a problem. Air Canada says the cabin will only carry “light weight boxes containing medical equipment.”

In-demand items like face masks and protective suits are volumetric, taking up space but not much weight. A box of face masks is larger than the box an iPhone comes in, but the iPhone box weighs more. Heavier items can be carried as usual in the below-deck cargo compartments.

What keeps boxes from moving? Freight aircraft have floors designed to lock cargo containers in place. Air Canada will use restraint nets that attach to seat tracks embedded in the floor. The quasi-freight conversion work was designed and implemented by aircraft maintenance company Avianor.

Seat tracks secure passenger seats up to a 16g impact, so there is logic in using the seat tracks to restrain cargo. Boeing mooted this method in a March memo to airlines about how it was studying restraining cargo in the cabin. “This evaluation includes the analysis of cargo restraints connected directly to the seat tracks to ensure structural loads are within design limits,” Boeing said.

Height restriction: Cargo in Air Canada’s 777 cabin can only be loaded up to 62” tall, less than the 118” limit on a full freighter. The overhead bins, which are not being removed, are not the limiting factor since they are placed higher than 62”.

A safety measure is likely the restriction: the size of cargo nets, or limiting cargo height so in the event of smoke or fire, an observer can see the top of all items.

Cabin crew onboard: Who exactly is that observer? Airbus, Boeing and IATA recommend cabin crew or other observers be onboard flights where cargo is carried in the passenger cabin. Regulators from India to Singapore are mandating it, although Air Canada did not specify details about onboard observers.

Lavatories have smoke detectors, as safety briefings announce. But the rest of the cabin does not, and there is no fire suppression system. So auxiliary crew – and not the pilots – need to patrol the cabin to look for any sign of danger, and address it. While passengers may ever only see flight attendants tend to hospitality matters, flight attendants are trained in firefighting and other emergency procedures.

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Designated areas only: Freighter aircraft can be packed wall-to-wall with cargo containers, but Air Canada’s 777 freighter shows markings on the floor to indicate where cargo can and cannot be placed. Authorities are being cautious in ensuring there is still unobstructed access throughout the cabin even without passengers onboard.

Individual boxes: Loading will be laborious and time-consuming since boxes will have to be individually brought onboard. A trail of boxes awaited a relief flight organized by Airbus using its A350-1000 demonstrator.

No cargo hatch: Similar to containers on a shipping boat, freight is often pre-assembled onto pallets that are then loaded into the aircraft’s cargo compartment.

These pallets are typically 88” or 96” wide, too big for the cabin’s 42” wide passenger door (see comparison in the below photo). When aircraft are fully converted to freighters, the fuselage is cut open, a cargo access hatch is installed and the fuselage is sealed. That is lengthy work and largely irreversible, and Air Canada only needs a temporary solution to freight demand.

Even if a pallet could fit through door, it would be challenging to manoeuvre it around interior walls, galleys and lavatories without uninstalling those monuments. Cargo compartments are wide open, allowing for easy manoeuvring of these pallets that are 125” long.